Bone health screening practices with dual-energy X-ray absorptiometry and prediction of abnormal results in pediatric inflammatory bowel disease.

OBJECTIVES: Pediatric patients diagnosed with inflammatory bowel disease (IBD) are at risk of suboptimal peak bone mass attainment. This study aimed to understand rates of bone health screening adherence, describe factors associated with dual-energy X-ray absorptiometry (DXA) acquisition, and identify factors associated with abnormal DXA. METHODS: We performed a retrospective cohort study of pediatric IBD patients over a 10-year time frame. We included IBD patients (2-20 years of age) enrolled in ImproveCareNow and excluded patients with primary metabolic bone disease. Time-to-event methods and multivariable logistic regression were employed to identify factors associated with DXA acquisition and abnormal DXA. RESULTS: In 676 patients, 464 (68.63%) pediatric patients with IBD had a risk factor for low bone mineral density (BMD); 137 (29.53%) underwent an initial DXA scan. Quiescent disease was significantly associated with a reduced likelihood of DXA (hazard ratio [HR]: 0.48; 95% confidence interval [CI]: 0.24-0.97), while weight z-score <-2 was significantly associated with DXA performance (HR: 2.07; 95% CI: 1.08-3.98). Abnormal DXA results (BMD z-score ≤-1) occurred in 59 (35.54%) individuals. After adjusting for visit diagnosis, delayed puberty, severe disease course, 6 months or greater of steroid exposure, and history of fracture, BMI z-score <-1 (odds ratio: 5.45; 95% CI: 2.41-12.33) was associated with abnormal DXA. CONCLUSIONS: DXA screening occurred in less than one-third of eligible pediatric IBD patients. Compliance was more common in patients with a weight z-score <-2 and less common in those with quiescent disease. BMI strongly predicted abnormal DXA results when adjusting for risk factors for abnormal BMD.

Heat shock factor 1 drives regulatory T-cell induction to limit murine intestinal inflammation.

The heat shock response is a critical component of the inflammatory cascade that prevents misfolding of new proteins and regulates immune responses. Activation of clusters of differentiation (CD)4+ T cells causes an upregulation of heat shock transcription factor, heat shock factor 1 (HSF1). We hypothesized that HSF1 promotes a pro-regulatory phenotype during inflammation. To validate this hypothesis, we interrogated cell-specific HSF1 knockout mice and HSF1 transgenic mice using in vitro and in vivo techniques. We determined that while HSF1 expression was induced by anti-CD3 stimulation alone, the combination of anti-CD3 and transforming growth factor ß, a vital cytokine for regulatory T cell (Treg) development, resulted in increased activating phosphorylation of HSF1, leading to increased nuclear translocation and binding to heat shock response elements. Using chromatin immunoprecipitation (ChIP), we demonstrate the direct binding of HSF1 to foxp3 in isolated murine CD4+ T cells, which in turn coincided with induction of FoxP3 expression. We defined that conditional knockout of HSF1 decreased development and function of Tregs and overexpression of HSF1 led to increased expression of FoxP3 along with enhanced Treg suppressive function. Adoptive transfer of CD45RBHigh CD4 colitogenic T cells along with HSF1 transgenic CD25+ Tregs prevented intestinal inflammation when wild-type Tregs did not. Finally, overexpression of HSF1 provided enhanced barrier function and protection from murine ileitis. This study demonstrates that HSF1 promotes Treg development and function and may represent both a crucial step in the development of induced regulatory T cells and an exciting target for the treatment of inflammatory diseases with a regulatory T-cell component. SIGNIFICANCE STATEMENT: The heat shock response (HSR) is a canonical stress response triggered by a multitude of stressors, including inflammation. Evidence supports the role of the HSR in regulating inflammation, yet there is a paucity of data on its influence in T cells specifically. Gut homeostasis reflects a balance between regulatory clusters of differentiation (CD)4+ T cells and pro-inflammatory T-helper (Th)17 cells. We show that upon activation within T cells, heat shock factor 1 (HSF1) translocates to the nucleus, and stimulates Treg-specific gene expression. HSF1 deficiency hinders Treg development and function and conversely, HSF1 overexpression enhances Treg development and function. While this work, focuses on HSF1 as a novel therapeutic target for intestinal inflammation, the findings have significance for a broad range of inflammatory conditions.

Understanding very early onset inflammatory bowel disease (VEOIBD) in relation to inborn errors of immunity.

Inflammatory bowel diseases (IBD) are multifactorial diseases which are caused by the combination of genetic predisposition, exposure factors (environmental and dietary), immune status, and dysbiosis. IBD is a disease which presents at any age, ranging from newborns to the elderly. The youngest of the pediatric IBD population have a more unique presentation and clinical course and may have a different etiology. Very early onset IBD (VEOIBD) patients, designated as those diagnosed prior the age of 6, have distinct features which are more frequent in this patient population including increased incidence of monogenetic causes for IBD (0%-33% depending on the study). This proportion is increased in the youngest subsets, which is diagnosed prior to the age of 2. To date, there are approximately 80 monogenic causes of VEOIBD that have been identified and published. Many of these monogenic causes are inborn errors of immunity yet the majority of VEOIBD patients do not have an identifiable genetic cause for their disease. In this review, we will focus on the clinical presentation, evaluation, and monogenic categories which have been associated with VEOIBD including (1) Epithelial cell defects (2) Adaptive immune defects, (3) Innate Immune/Bacterial Clearance and Recognition defects, and (4) Hyperinflammatory and autoinflammatory disorders. We will highlight differential diagnosis of VEOIBD presentations, as well as evaluation and treatment, which will be helpful for those who study and care for VEOIBD patients outside of the pediatric gastroenterology field. This is a fast-moving field of research which has grown significantly based on knowledge that we gain from our patients. These scientific findings have identified novel mucosal biology pathways and will continue to inform our understanding of gastrointestinal biology.

The TNFΔARE Mouse as a Model of Intestinal Fibrosis.

Crohn disease (CD) is a highly morbid chronic inflammatory disease. Although many patients with CD also develop fibrostenosing complications, there are no medical therapies for intestinal fibrosis. This is due, in part, to a lack of high-fidelity biomimetic models to enhance understanding and drug development, which highlights the need for developing in vivo models of inflammatory bowel disease-related intestinal fibrosis. This study investigates whether the TNFΔARE mouse, a model of ileal inflammation, also develops intestinal fibrosis. Several clinically relevant outcomes were studied, including features of structural fibrosis, histologic fibrosis, and gene expression. These include the use of a new luminal casting technique, traditional histologic outcomes, use of second harmonic imaging, and quantitative PCR. These features were studied in aged TNFΔARE mice as well as in cohorts of numerous ages. At >24 weeks of age, TNFΔARE mice developed structural, histologic, and transcriptional changes of ileal fibrosis. Protein and RNA expression profiles showed changes as early as 6 weeks, coinciding with histologic changes as early as 14 to 15 weeks. Overt structural fibrosis was delayed until at least 16 weeks and was most developed after 24 weeks. This study found that the TNFΔARE mouse is a viable and highly tractable model of ileal fibrosis. This model and the techniques used herein can be leveraged for both mechanistic studies and therapeutic development for the treatment of intestinal fibrosis.

Early Anti-Tumor-Necrosis-Factor Therapy for Crohn's Disease-Related Abdominal Abscesses and Phlegmon in Children.

BACKGROUND: Internally penetrating Crohn's Disease complications, including abscesses and phlegmon, represent a high-risk Crohn's Disease phenotype. Anti-tumor-necrosis-factor-α (Anti-TNF) therapies are effective in treating penetrating Crohn's Disease and early initiation has shown unique benefits. However, timing of anti-TNF initiation in the setting of internally penetrating Crohn's Disease complications is typically heterogenous due to concern over precipitating serious infections. Recent studies demonstrate such an association may not exist. AIMS: We aimed to describe the multidisciplinary management of pediatric patients with internally penetrating Crohn's Disease complications, focusing on the utilization and timing of anti-TNF therapy relative to complication resolution and adverse events. METHODS: We performed a single-center retrospective cohort study of pediatric patients with internally penetrating Crohn's Disease complications from 2007 to 2021. The safety and effectiveness of anti-TNF therapy initiation prior to complication resolution was assessed by comparing rates of infectious and Crohn's Disease-related adverse events between those who received anti-TNF therapy prior to complication resolution, versus those who did not. RESULTS: Twenty-one patients with internally penetrating Crohn's Disease complications were identified. 7/21 received anti-TNF therapy prior to complication resolution. Infectious adverse events within 90 days of complication occurred in 0/7 patients initiating anti-TNF therapy prior to complication resolution and 10/14 patients who did not (p = 0.004). Crohn's Disease-related surgeries and hospitalizations within 1 year of complication occurred in 12/20 patients, with similar frequency between groups. CONCLUSIONS: Initiating anti-TNF therapy prior to internally penetrating Crohn's Disease complication resolution may be a safe and effective strategy to improve clinical outcomes.

Characteristics of Children With Inflammatory Bowel Disease and Coexisting Celiac Disease Seropositivity.

OBJECTIVES: Celiac disease (CeD) autoimmunity and coexisting inflammatory bowel disease (IBD) present a diagnostic dilemma. Our aims were to describe the phenotype of children with IBD and CeD seropositivity and evaluate provider confidence for diagnosing CeD in this population. METHODS: We performed a single-center retrospective cohort study of subjects ≤18 years old with IBD and CeD seropositivity between 2006 and 2020. Subjects were considered to have IBD-CeD if they met CeD diagnosis by serology and histology per North American Society For Pediatric Gastroenterology, Hepatology and Nutrition guidelines and if providers suspected CeD as evaluated by a survey. The IBD-only cohort included seropositive participants that did not meet criteria for CeD. Demographic, histologic, gross endoscopic, and laboratory features were compared using Fisher exact test. RESULTS: Of 475 children with IBD, 8 had concomitant CeD, 5 had tissue transglutaminase (tTG) immunoglobulin A (IgA) > 10x upper limit of normal (ULN, P = 0.006), and 8 had villous atrophy (VA, P = 0.003) when compared with 17 seropositive participants with IBD-only. No children with IBD-CeD had esophageal eosinophilia, duodenal cryptitis, duodenal ulceration, or fecal calprotectin >250 µg/g. Factors that contributed to provider uncertainty for diagnosing CeD in IBD included the absence of VA and intraepithelial lymphocytes, the presence of neutrophilic and eosinophilic duodenitis, diffuse ulceration, elevated inflammatory markers, and immunosuppression therapy. CONCLUSIONS: Diagnosing CeD in children with IBD continues to be challenging. Although high titers of tTG IgA and VA increased provider confidence for diagnosing CeD in IBD, development of evidence-based guidelines are needed. They should better assess the importance of features atypical of concomitant CeD that contribute to uncertainty.

Delays Related to Prior Authorization in Inflammatory Bowel Disease.

BACKGROUND: Delays in advancing to biologic therapies are associated with adverse outcomes in inflammatory bowel disease (IBD). Insurer-mandated prior authorizations have been linked to prolonged medication initiation times. We hypothesized that prior authorizations are associated with prolonged biologic initiation time and increased IBD-related healthcare utilization among children with IBD. METHODS: We performed a retrospective cohort study of 190 pediatric patients with IBD initiating biologics at a tertiary care hospital to measure the association between prior authorization, biologic initiation time (physician recommendation to first dose), and healthcare utilization (hospitalization, surgery, or emergency department visit). Demographic, insurance, and disease severity-related covariables were collected. Multivariable linear regression was used to measure the association between prior authorization and biologic initiation time. Propensity score methods were used to measure the associations between prior authorization and IBD-related healthcare utilization within 180 days and corticosteroid dependence at 90 days, with adjustment for insurance type, demographics, and disease severity-related characteristics. RESULTS: Median biologic initiation time was 21 days. Prior authorization and complicated prior authorizations (requiring appeal, step therapy, or peer-to-peer review) were associated with 10.2-day (95% confidence interval [CI] 8.2 to 12.3) and 24.6-day (95% CI 16.4 to 32.8) increases in biologic initiation time, respectively. Prior authorizations increased the likelihood of IBD-related healthcare utilization within 180 days by 12.9% (95% CI 2.5 to 23.4) and corticosteroid dependence at 90 days by 14.1% (95% CI 3.3 to 24.8). CONCLUSIONS: Prior authorizations are associated with prolonged biologic initiation time and increased IBD-related healthcare utilization. Minimizing prior authorization-related delays may expedite biologic delivery and reduce the risk of IBD-related healthcare utilization.

Efficacy and Outcomes of Faecal Microbiota Transplantation for Recurrent Clostridioides difficile Infection in Children with Inflammatory Bowel Disease.

BACKGROUND: Children with inflammatory bowel disease [IBD] are disproportionally affected by recurrent Clostridioides difficile infection [rCDI]. Although faecal microbiota transplantation [FMT] has been used with good efficacy in adults with IBD, little is known about outcomes associated with FMT in paediatric IBD. METHODS: We performed a retrospective review of FMT at 20 paediatric centres in the USA from March 2012 to March 2020. Children with and without IBD were compared with determined differences in the efficacy of FMT for rCDI. In addition, children with IBD with and without a successful outcome were compared with determined predictors of success. Safety data and IBD-specific outcomes were obtained. RESULTS: A total of 396 paediatric patients, including 148 with IBD, were included. Children with IBD were no less likely to have a successful first FMT then the non-IBD affected cohort [76% vs 81%, p = 0.17]. Among children with IBD, patients were more likely to have a successful FMT if they received FMT with fresh stool [p = 0.03], were without diarrhoea prior to FMT [p = 0.03], or had a shorter time from rCDI diagnosis until FMT [p = 0.04]. Children with a failed FMT were more likely to have clinically active IBD post-FMT [p = 0.002] and 19 [13%] patients had an IBD-related hospitalisation in the 3-month follow-up. CONCLUSIONS: Based on the findings from this large US multicentre cohort, the efficacy of FMT for the treatment of rCDI did not differ in children with IBD. Failed FMT among children with IBD was possibly related to the presence of clinically active IBD.

Parent Perspectives on Exclusive Enteral Nutrition for the Treatment of Pediatric Crohn Disease.

OBJECTIVES: Exclusive enteral nutrition (EEN) is infrequently used in the United States but is an effective treatment for pediatric Crohn disease (CD). Limited data exists regarding patient and parent perspectives on this treatment modality. The aim of this study was to determine parent and provider perspectives regarding EEN and understand parent-cited barriers to its use. METHODS: We surveyed the parents/guardians of children ages 1 through 17 with CD in our institution regarding EEN. Healthcare provider perspectives regarding reason for stopping EEN and those cited by survey respondents were compared using retrospective chart review. RESULTS: One hundred fifteen (62.5%) out of 184 recipients responded to the survey. Ninety percentage of respondents had heard of EEN but of these, 26% had not discussed it with their gastroenterologist. Thirty-eight patients (33%) were treated in the past and 15 (13%) were currently on EEN. Common barriers cited by current EEN users were cost/finances and difficult social situations. Of the children who stopped EEN, most did so as parents felt it was not working (n = 14, 37%). In these cases, their primary gastroenterologist cited treatment failure for 4 cases and nonadherence for 6. CONCLUSIONS: Despite the efficacy of EEN and interest in dietary treatments by patients with CD, there are many barriers surrounding effective communication and successful implementation of dietary therapies. Future research is needed regarding patient-physician communication, cost mitigation, and coping with the social limitations of dietary therapies.

Challenges in IBD Research: Precision Medicine.

Precision medicine is part of five focus areas of the Challenges in IBD research document, which also includes preclinical human IBD mechanisms, environmental triggers, novel technologies, and pragmatic clinical research. The Challenges in IBD Research document provides a comprehensive overview of current gaps in inflammatory bowel diseases (IBD) research and delivers actionable approaches to address them. It is the result of a multidisciplinary input from scientists, clinicians, patients, and funders, and represents a valuable resource for patient centric research prioritization. In particular, the precision medicine section is focused on highlighting the main gap areas that must be addressed to get closer to treatments tailored to the biological and clinical characteristics of each patient, which is the aim of precision medicine. The main gaps were identified in: 1) understanding and predicting the natural history of IBD: disease susceptibility, activity, and behavior; 2) predicting disease course and treatment response; and 3) optimizing current and developing new molecular technologies. Suggested approaches to bridge these gaps include prospective longitudinal cohort studies to identify and validate precision biomarkers for prognostication of disease course, and prediction and monitoring of treatment response. To achieve this, harmonization across studies is key as well as development of standardized methods and infrastructure. The implementation of state-of-the-art molecular technologies, systems biology and machine learning approaches for multi-omics and clinical data integration and analysis will be also fundamental. Finally, randomized biomarker-stratified trials will be critical to evaluate the clinical utility of validated signatures and biomarkers in improving patient outcomes and cost-effective care.

A novel human IL2RB mutation results in T and NK cell-driven immune dysregulation.

The pleiotropic actions of interleukin-2 (IL-2) are essential for regulation of immune responses and maintenance of immune tolerance. The IL-2 receptor (IL-2R) is composed of IL-2Rα, IL-2Rß, and IL-2Rγ subunits, with defects in IL-2Rα and IL-2Rγ and their downstream signaling effectors resulting in known primary immunodeficiency disorders. Here, we report the first human defect in IL-2Rß, occurring in two infant siblings with a homozygous IL2RB mutation in the WSXWS motif, manifesting as multisystem autoimmunity and susceptibility to CMV infection. The hypomorphic mutation results in diminished IL-2Rß surface expression and dysregulated IL-2/15 signaling, with an anticipated reduction in regulatory T cells. However, in contrast to the IL-2Rß-/- animal model, which lacks NK cells, these siblings demonstrate an expansion of NK cells, particularly the CD56bright subset, and a lack of terminally differentiated NK cells. Thus, the early-onset autoimmunity and immunodeficiency are linked to functional deficits arising from altered IL-2Rß expression and signaling in T and NK cells.

miR-106a deficiency attenuates inflammation in murine IBD models.

Pro-inflammatory cytokine TNFα antagonizes regulatory T cell (Treg) suppressive function with a measurable reduction of IL-10 protein secretion. Tregs are critical to suppress excessive immune activation, particularly within the intestine where high antigenic loads elicit chronic subclinical immune activation. Employing a TNFα-driven murine inflammatory bowel disease (IBD) model (TNFΔARE/+), which mirrors the Treg expansion and transmural ileitis seen in Crohn's disease, we demonstrate that the TNFα-mediated loss of Treg suppressive function coincides with induction of a specific miRNA, miR-106a in both humans and mice, via NFκB promoter binding to suppress post-transcriptional regulation of IL-10 release. Elevation of miR-106a and impaired Treg function in this model recapitulate clinical data from IBD patients. MiR-106a deficiency promotes Treg induction, suppressive function and IL-10 production in vitro. MiR-106a knockout attenuated chronic murine ileitis, whereas T cell restricted deficiency of miR-106a attenuated adoptive transfer colitis. In both models, attenuated inflammation coincided with suppression of both Th1 and Th17 cell subset expansion within the intestinal lamina propria. Collectively, our data demonstrate impaired Treg suppressive function in a murine IBD model consistent with human disease and support the potential for inhibition of miR-106a as a future therapeutic approach to treat chronic inflammatory conditions including IBD.

C/EBPß Deletion Promotes Expansion of Poorly Functional Intestinal Regulatory T Cells.

BACKGROUND AND AIMS: Inflammatory Bowel Diseases [IBDs] are chronic intestinal inflammatory conditions in part mediated by CD4+ T cells. Anti-inflammatory Foxp3+ regulatory T cells [Tregs] maintain immune homeostasis and protect against IBD development via multiple mechanisms, including cytokine secretion and cell-cell interaction. CCAAT enhancer binding protein-beta [C/EBPß] is a stress-responsive transcription factor linked with IBD susceptibility. Whole-body C/EBPß deficiency induces CD4+ T cell-predominant hyperproliferation, and we hypothesize that this may be due to impaired Treg function. METHODS: We used the C/EBPß-/- mice in the CD45RBHigh adoptive transfer model, to assess C/EBPß-/- CD4+ T cells for their colitiogenic potential, and C/EBPß-/- CD4+ Foxp3+ Tregs for their ability to inhibit colitis. We assessed Tregs from the C/EBPß-/- mice for expression of Treg functional genes and proteins. RESULTS: Naïve C/EBPß-/- CD4+ T cells are more colitogenic in vivo. The exacerbated colitis does not appear to reflect impaired Treg development, however, as C/EBPß-/- mice displayed more, rather than fewer intestinal CD4+Foxp3+ Tregs in vivo. Instead, this reflects impaired Treg function as seen by the reduced capacity to suppress T cell proliferation in vitro, along with decreased secretion of the anti-inflammatory cytokine IL-10. These findings were corroborated in vivo by additional adoptive co-transfer studies in which wildtype Tregs prevented colitis but C/EBPß-/- Tregs did not. CONCLUSION: C/EBPß deficiency impairs Treg function and potentiates T cell-mediated colitis. A clearer understanding of the function of this transcription factor may provide a novel therapeutic strategy for IBD.